SoftBank's Masayoshi Son has been widely recognized as one of the world's largest tech investors and also a billionaire. Now he is facing one of the toughest moments in his life. His $100 billion Vision Fund lost billions of dollars from multiple bad investments; SoftBank would likely take its first annual loss in 15 years; an activist investor is also trying to take over more control of SoftBank. Business Insider spoke with more than a dozen people who had contact with him, to understand what motivates him in investment and how he might find his way out of his current predicament. source